Glucose and glycohemoglobin in blood are measured to perform a screening test and treatment of diabetes.
A method of measuring the glucose in the blood includes a method called an electrode method. This method is a method of outputting information correlated to a glucose concentration in a blood sample to an electrode brought into contact with the blood sample, and calculating the glucose concentration based on such output (see e.g., Patent Documents 1 and 2). The electrode method can be roughly classified into an equilibrium point method (end point method) and a differentiation method (rate method) depending on a calculation technique thereof. The equilibrium point method is a method of calculating the glucose concentration based on an equilibrium value of when a temporal change of the output from the electrode asymptotically approaches a constant value. On the other hand, the differentiation method is a method of calculating the glucose concentration based on a maximum value of when the output is differentiated n times (n is a positive integer). The electrode method also includes a method of associating a calculation result in the equilibrium point method and a calculation result in the differentiation method.
A liquid chromatography method is widely used for the method of measuring the glycohemoglobin (see e.g., Patent Documents 3 and 4). In this method, the glycohemoglobin is calculated as a proportion the glycohemoglobin occupies in a hemoglobin content based on a chromatogram indicating a relationship between elution time and elution amount (e.g., optical information such as absorbance).
At clinical sites, both the glucose and the glycohemoglobin are measured to treat the diabetes. Thus, an analysis apparatus and an analyzing system capable of measuring both the glucose and the glycohemoglobin are being developed and sold.
An analysis apparatus for measuring both the glucose and the glycohemoglobin includes an analysis apparatus in which a mechanism for measuring the glucose and a mechanism for measuring the glycohemoglobin are integrated in one device (“DM-JACK”: manufactured by Kyowa Medex Co., Ltd.). This analysis apparatus adopts an enzyme method, which is a biochemical method, for the glucose measurement method and an immunization method for the glycohemoglobin measurement method.
As shown in FIG. 11, an analyzing system 9 for measuring both the glucose and the glycohemoglobin includes an analyzing system in which a glucose measurement device 90 and a glycohemoglobin measurement device 91 are coupled for use (“HA70/GA70 simple conveying system”: manufactured by ARKRAY Inc., system combining “HLC723 G8” (manufactured by Tosoh Corporation) and “GA08” (manufactured by A&T Corporation)).
Such a system 9 uses a device for measuring the glucose through the electrode method for the glucose measurement device 90, and a device for measuring the glycohemoglobin through the HPLC method for the glycohemoglobin measurement device 91. The analyzing system 9 couples the glucose measurement device 90 and the glycohemoglobin measurement device 91, and commonly uses one specimen conveying mechanism 92 in the devices 90 and 91. The specimen conveying mechanism 92 is configured to move a blood collecting tube 93 from a position where a specimen can be collected from the blood collecting tube 93 in the glucose measurement device 90 to a position where a specimen can be collected from the blood collecting tube 93 in the glycohemoglobin measurement device 91. In other words, the analyzing system 9 is configured such that the specimen collected from the blood collecting tube 93 in the glucose measurement device 90 is introduced into a reaction bath 94 to measure the glucose concentration, while the specimen collected from the blood collecting tube 93 in the glycohemoglobin measurement device 91 is introduced into an injection valve 95 to measure the glycohemoglobin.
However, the conventional analysis apparatus and the analyzing system 9 perform sampling of the specimen and preparation of the sample for measuring the glucose concentration, and the sampling of the specimen and the preparation of the sample for measuring the glycohemoglobin concentration independently. In other words, although the concentrations of both the glucose and the glycohemoglobin can be measured in the conventional analysis apparatus and the analyzing system 9, the sampling of the specimen and the preparation of the sample each need to be carried out twice to measure the concentration of the respective components. Thus, in the conventional analysis apparatus and the analyzing system 9, a configuration of the device or the system becomes complicated and a size of the device or the system is enlarged. In particular, since the analyzing system 9 is obtained by simply coupling two existing devices 90 and 91, a user is imposed with the same load as when using two devices. That is, the glucose measurement device 90 and the glycohemoglobin measurement device 91 need to be operated independently to measure the glucose concentration and the glycohemoglobin concentration, and the devices 90 and 91 need maintenance to be performed independently. In addition, as a portion related to measurement is not commonly shared at all in the two devices 90 and 91, an installation area for two devices is necessary, and a cost of the specimen conveying mechanism 92 is necessary in addition to a cost for the two devices.
Furthermore, in the above-described analysis apparatus, measurement accuracy of the glycohemoglobin concentration is not satisfactory since the immunization method is adopted for the measurement method of the glycohemoglobin concentration.
[Patent Document 1] Japanese Unexamined Patent Publication No. 9-33533
[Patent Document 2] Japanese Unexamined Patent Publication No. 2005-148058
[Patent Document 3] Japanese Unexamined Patent Publication No. 5-5730
[Patent Document 4] Japanese Unexamined Patent Publication No. 9-178719